Web tension control is important in paper conversion processes and the like. In high speed operations, even relatively small variations in web tension may cause web processing difficulties downstream. Moreover, in relatively high speed web lines, such as those exceeding about 500 feet per minute (about 150 meters per minute), manual adjustment of web tension is not practical.
In web tensioning systems where web tension is controlled or maintained by a dancer, a limitation on effective control of web tension is the response time of the dancer inasmuch as often the dancer movement lags behind the actual changes in web tension. A primary cause of such relatively long response time is the weight of the dancer. Thus, it would be desirable to have a web tensioning device that responds readily to variations in web tension with minimum lag time. The present invention satisfies this need.